Some Visiobraille braille terminals (TVB) need a peculiar serial flowcontrol:- There is no flow control for the PC -> device way (yes, oddly enough)- For the device -> PC way, * RTS must be kept low, the device keeps CTS low as well. * when the device wants to send data, it raises CTS. RTS must be raised as well. Data can then pass, CTS and RTS are lowered.

We tried to implement that in user space, with ioctl(TIOCMBIS) & al, butthe responsiveness is too low: RTS is not raised soon enough, and thedevice aborts transmission.

Here is a patch for 2.4, a 2.6 patch is coming in another mail. Itdefines a CTVB flag the same way CRTSCTS is defined, letting userspace choose whether to use it or not (better ideas for the nameare welcome). This makes the device work perfectly (even better thanshipped drivers for DOS).

Applying it to vanilla kernel would be a real good thing for peoplehaving such costly and useful hardware.